Attachment plug receptacle



Oct. 11, 1938. f G. A. JoHNsoN 2,132,851

ATTACHMENT PLUG REGEPTACLE Filed April 27. 193s ILII 7 Patented Oct. 11, 1938 UNiTED STATES ATTACHMENT PLUG RECEPTACLE Gustaf A. Johnson Application April 27,

6 Claims.

This invention relates to an attachment plug receptacle.

The main object of the invention is the provision of a device of the above character which is simple in construction, yet eicient and durable.

Another object of the invention is to eliminate so far as possible in a device of that character the use of the screws and similar means now used for fastening the various elements of the structure in the insulating body and thereby material- 1y reduce the cost of manufacture.

Another object is the provision of an insulating body having integral extensions formed to receive means for fastening said body directly to an outlet box thereby eliminating metallic straps and other devices now used for that purpose.

Another object of the invention is the provision of contact members in which breakage due to crystallization of the contact blades is entirely eliminated so that the life of the said members is indefinitely extended.

A further object is the provision of means whereby an efficient contact between the contact portions and the jack blades of an attachment plug inserted in the receptacle is always assured.

An additional object is the provision of a construction in which the insertion of the binding screws in the contact members locks those members within the insulating body without requiring other fastening means.

Another object is the provision of a construction which permits the insulating cover for the recessed bottom of the receptacle to be locked in position without requiring fastening means.

Other objects of the invention will be in part obvious and in part described hereinafter.

Briefly, my invention contemplates the provision of an insulating body recessed to afford a plurality of contact chambers opening out the front face thereof through slots adapted for receiving the jack blades of an attachment plug and suitable contacts mounted in said chambers. As embodied in a receptacle of the duplex type, the invention contemplates an insulating body having four contact chambers, the two chambers on each side of the receptacle being connected together by a narrow slot adapted to receive and house a contact plate inserted edgewise, said plate having end portions extending into the two chambers and formed to serve as contact blades.

One of the important features of the invention resides in the form of the contact plate which is an elongated, flat metal strip, free of abrupt curves or bends, the contact blade at eachV end New Bedford, Mass.

1935, Serial No. 18,587

being partially separated from the main body of the plate and having its free end slightly offset in relation to the main body of said contact plate. 'I'his eliminates any sharp curves or bendings in the contact plate and thereby prevents the crystallization of the metal which occurs when the contact blade portions are hinged on a fold or bend, which causes in these devices the breakage of the blades at the fold o1' bend. By providing a contact plate which is flat and free from bends or folds, crystallization is practically eliminated so that the life of the contact is extended indenitely.

'Another feature of the invention consists in utilizing the binding screws carried by the contac'tplates for locking them within the insulating body to eliminate other fastening means. This end is accomplished by inserting the binding screws through the side walls of the insulating body and into the contact plates, which prevents the plates from being withdrawn from said body and, at the same time, permits the lead wires to be fastened under the heads ofthe binding screws on the outer sides of the receptacle.

Another feature `of the invention resides in the provision of resilient means for holding the contact blades at all times in position to make efcient contacts with the blades of a plug inserted in the receptacle. One embodiment of this means comprises a spring mounted under compression in a passage connecting the two contact chambers at each end of the insulating body, the ends of said spring carrying insulating plugs which bear against the two contact blades in said chambers to hold them in proper position.

A further feature of the invention consists in providing an insulating cover for the bottom of the insulating body which may be locked to the body without requiring the usual fastening screws employed for this purpose and one form of this means consists in providing the insulating cover with side extensions adapted for insertion in suitable recesses in the bottom face of said body and having openings adapted to be engaged by struck out lugs on the contact plates.

Yet another feature of the invention resides in the provision of an insulating body adapted to be molded from suitable material and having integral end extensions provided with openings which permit the insulating body to be fastened directly to an outlet box, thereby rendering unnecessary the metallic supporting strap or other devicesnow used for accomplishing this end.

This feature, however, in itsbroader aspects is disclosed and claimed in another application for United States Letters Patent filed by me in the United States Patent Oice April 27, 1935, Serial No. 18,588.

My invention comprises various other features which will be more specifically described hereinafter.

In the accompanying drawing showing one form of the invention for the purpose of illustrating the principle thereof, Figure 1 is a front elevation of a receptacle constructed in accordance with my invention and shown with a wall plate of usual construction, a portion of the latter being broken away to show the under portion of the receptacle;

Fig. 2 is a side elevation of the same;

Fig. 3 is a longitudinal, vertical, sectional View of same on line 3 3 in Figure 1;

Fig. 4 is a bottom plan view on an enlarged scale of the receptacle with the insulating cover removed to show the interior construction;

Fig. 5 is a cross-sectional view of same on line 5 5 in Fig. 4;

Fig. 6 is a side elevation of a contact plate;

Fig. 7 is an end elevation of the same;

Fig. 8 is a View 0f the plate for backing the contact and for holding the ends of the binding screws;

Fig. 9 is a bottom plan view on an enlarged scale of an insulating body of slightly modified construction, permitting the use of an insulating cover adapted to be mounted in the body without requiring the use of fastening screws;

Fig. 10 is a plan view of the form of cover to be used in the body illustrated in Fig. 9;

Fig. 1l is a cross-sectional view on line IfI-II in Fig. 9 showing the cover of Figure l0 locked in the body; and

Fig. 12 is a plan View of a modified form of contact plate adapted for locking the cover in place.

Referring to the drawing showing the invention as embodied in a receptacle of the duplex type, I5 designates a one-piece insulating body of any suitable form, but preferably rectangular, provided on its upper face with a pair of enlarged projecting bosses I6 adapted to fit openings in the ordinary wall plate I1. In its bottom face, the insulating body is recessed to form a plurality of contact chambers 2li, which, in the form shown, number four, each of which opens. out the front face of the insulating body through slots 2l adapted to receive the jack blades of an insulating plug. The two contact chambers on each side of the insulating body are connected by a longitudinal slot 22 adapted to receive and house the main body portion of a contact plate 2'4 having at each end a partially separated Contact blade 25. rIhe contact plate is flat and free from any abrupt curves or folds. The endsl ofthe contact blades 25 are in a slightly offset relation to the main body portion of the contact plate but this is accomplished without abrupt curving of the metal which would centralize crystallization and lead to breakage. Y

The jack blade slots 2i are offset in relation to the contact chambers and are of narrower width than said chambers to form a shoulder 21 in each chamber adjacent the front face of said receptacle and the contact plate hasv a slightly turned flange 28 at each end adapted to engage said shoulder in the contact chamber for limiting the inward movement of the contact plate.

The two contact chambers 7.!) at each end of the insulating body I5 are connected together by a passage 30, in which passage is mounted under compression a helical spring 3l carrying in each end an insulating plug 32 which is adapted to bear against the free end of a contact blade 25 for holding it against the inner face of the side wall of the insulating body in position to be engaged by a jack blade inserted in the slot 2l.

The side walls of the insulating body are bored to receive on each side one or more binding screws 35, the ends of which pass through suitable openings in the main body of each contact plate and are threaded into a backing plate or nut 36. The plate or nut 35 may be dispensed with, if desired, by making the body portion of the contact plate 22 of a thickness sufficient to provide threaded holes for receiving the ends of the binding screws. The binding screws 35 thereby serve to lock the contact plates within the insulating body and at the same time permit the lead wires 31 to be connected to their heads on the outer faces of the two sides of the said body.

Suitable recesses 38 are provided in the insulating body for accommodating the endsl oi the binding screws. Projecting ribs 49 may be formed on the sides of the Vinsulating body to hold the lead wires under the heads of the binding screws. If preferred, a single binding screw may be used on each side of the insulating body in place of the two shown, with ribs 48 on both sides permitting the attachment of a pair of lead wires thereto.

For closing the bottom face of the insulating body, a plate or cover 42 of paper or other insulating material, may be fastened in countersunk relation to the body by a pair of screws 43.

In Figures 9 to 12 inclusive, I have shown a modied form of insulating plate or cover 45 for closing the bottom of the insulating body I5, which plate is so designed as to eliminate the use of screws 43 for fastening it to the insulatingbody. The latter is slightly modified in construction, having portions` of the abutments 4l cut out along the side walls to form recesses 48 for receiving certain portionsv of the plate. The insulating plate 45 comprises a body portion having side extensions 49 each provided with an aperture 50, these extensions being adapted to be bent at right angles to the main body portion of the plate and inserted in the recesses 48 and each contact plate is modified to the extent of having an ear 52 pressed outwardly from its body portion so as to engage the aperture 50 in the side extension 49 of the plate 45 for holding it locked within the insulating body after insertion.

It is to be noted that the assembling opera- H tion in the making of receptacles of my invention is much simplied because the insulating body and the parts carried by it are so formed that those parts are locked in position within the insulating body without requiring additional fastening means, such as screws and the like. In assembling a receptacle, the contact plates are pushed edgewise into their proper places in the insulating body, the binding screws inserted through the side walls and into place, the springs carrying the insulating plugs are pushed in place between opposite contact blades and the insulating cover or plate is then fastened in place. This completes the assembling. If the cover or plate shown in Fig. 3 is used, it is fastenedV with the two screws 43, but if the modified form of Contact plates and insulating cover or'plate is used, then the latter is merely pushed into position and locked on the contact plates without using any GII other fastening means. In such case, the assem- 'l5 vplate to serve as a contact blade, the top edge of bling operation involves no use of fastening means and the time and labor required in the operation is thereby greatly reduced and there is a saving in labor and materials due to the elimination of the usual fastening means.

In the use of attachment plug receptacles, they are usually installed in and fastened to suitable outlet boxes set in the walls. Heretofore, these receptacles have been provided with metallic straps which have been fastened to the insulating body by screws or other means and which have had end portions slotted to receive screws or other means for fastening the device in an outlet box.

To eliminate th-e use of supporting straps or other such devices, my invention contemplates the provision of end extensions 60 upon the insulating body l5, which extensions are provided with slots 52 for receiving screws or other means for fastening the receptacle in and to an outlet box.

The insulating body I is designed to be molded from any suitable insulating material such as a phenolic condensation product, porcelain or other material and, therefore, the formation of the end extensions thereon in the molding process involves no appreciable increase in cost.

After the insulating body has been mounted .in and fastened to an outlet box in a wall opening, the wall plate il is then adjusted, as shown in Figure 1 of the drawing, to cover up and conceal all of the insulating body except the projecting bosses i6 and is fastened to the insulating body by a single screw 10.

It is to be observed that a receptacle made in accordance with my invention is of very simple and very eicient construction and can be made at a very low cost. Because all breakages of the contact members are eliminated, the life of the receptacle is indefinitely extended.

It is to be understood that my invention is not to be limited to the specific form of device herein shown and described or to the specific forms of the elements which are comprised in it, since theY invention may be embodied in various other forms within the purview of the following claims.

What I claim is:

1. In a device of the character described, the combination with an insulating body recessed in its bottom face and a pair of contact plates mounted in said recess, each of said plates having a struck out projection or tongue, of a cover of insulating material for closing the bottom face of said body, said cover having side extensions seated in said recess and having each an opening adapted to be engaged by one of said projections or tongues for locking said cover to said body.

2. In a device of the character described, the combination of an insulating body recessed in its bottom face to form a pair of separate contact chambers at each endconnected together by a transverse passage, each chamber opening out the top face of said body through a jack blade slot, said slot being oilset in an outward direction to form an inner shoulder in said chamber, adjacent said top face, the two chambers on each side of said body being connected by a longitudinal slot parallel to the side wall, said longitudinal slot having its two end portions of restricted width to prevent lateral movement of a contactl plate inserted therein, a contact plate mounted edgewise in each of said slots, each' of said contact plates having at each end a portion projecting into one of said contact chambers, each of said end portions being partially separated from the bottom edge upwardly and transversely of said same being turned inwardly to engage the said inner'shoulder in said chamber for locking said `blade therein, and an insulated helical spring l-mounted in each of said transverse passages and interposed between the lower ends of the contact blades at each end of said body for holding them in jack blade engaging position.

3. In a device of the character described, the combination of an insulating body recessed in its bottom face to form a pair of separate contact chambers at each end connected together by a transverse passage, each chamber opening out the top face of said body through a jack blade slot, said slot being offset in an outward direction to form an inner shoulder in said chamber adjacent said top face, the two chambers on each side of said body being connected by a longitudinal slot parallel to the side wall, said longitudinal slot having its two end portions of restricted width to prevent lateral movement of a contact plate inserted therein, a contact plate mounted edgewise in each of said slots, each of said contact plates having at each end a portion projecting into one of said contact chambers, each of said en-d portions being partially separated from the bottom edge upwardly and transversely of said plate to serve as a contact blade, the top edge of same being turned inwardly to engage the said inner shoulder in said chamber for locking said blade therein, resilient means mounted in the transverse passage and interposed between the lower ends of the contact blades at each end of said body for holding them in jack blade engaging position and a binding screw on each side of said body extending inwardly through a side wall thereof and having its end threaded into a contaotplate for holding the same within said insulating body without other supporting means, the head of said screw being on the outer face of sai-d side wall for permitting a lead wire to be attached thereto at the side of the said body.

ll. In a device of the character described, the combination with an insulating body recessed in its bottom face, and a pair of contact plates mounted edgewise in said recess, each of said plates having a struck-out projection, of a cover of insulating material for closing the bottom face of said body, said cover having side extensions seated in said recess, each of said extensions having an opening adapted to be engaged by one of said projections for locking said cover to said body.

5. A device of the character described comprising an elongated insulating body recessed in its bottom face to form a relatively wide central abutment extending longitudinally of said body and on each end of said abutment a pair of separate contact chambers, said chambers being connected together by a longitudinal slot adjacent each side of said body and each of said chambers opening out the top face of said body through an offset jack blade slot and having an inner shoulder adjacent said top face, an elongated contact plate mounted edgewise in each of said slots and having each end provided with a contact blade lying in one of said chambers, each of said contact blades having its top edge in engagement with the inner shoulder in said chamber, the two chambers at each end of said body being connected together by a transverse passage in said abutment and a spring mounted in each of said transverse passages for holding the contact blades in the adjacent chambers in jack blade engaging. position.

6. A device of the character described comprising an' elongated insulating body recessedv in its bottom face to form a relatively wide central abutment extending longitudinally of said body and on each end of said abutment a pair of separate contact chambers, said chambers being connected together by a longitudinal slot adjacent each side of said body and each of said chambers' opening out the top face of said body through an offset jack blade slot and having an inner shoulderv adjacent said top face, an elongated contact plate mounted edgewise in each GUSTAF A. JOHNSON. 

